Aspects of the present disclosure relate generally to wireless communication systems, and more particularly, to handling stale or incomplete packet data units (PDUs or packets) in a wireless network.
Wireless communication networks are widely deployed to provide various communication services such as telephony, video, data, messaging, broadcasts, and so on. Such networks, which are usually multiple access networks, support communications for multiple users by sharing the available network resources. One example of such a network is the UMTS Terrestrial Radio Access Network (UTRAN). The UTRAN is the radio access network (RAN) defined as a part of the Universal Mobile Telecommunications System (UMTS), a third generation (3G) mobile phone technology supported by the 3rd Generation Partnership Project (3GPP). The UMTS, which is the successor to Global System for Mobile Communications (GSM) technologies, currently supports various air interface standards, such as Wideband-Code Division Multiple Access (W-CDMA), Time Division-Code Division Multiple Access (TD-CDMA), and Time Division-Synchronous Code Division Multiple Access (TD-SCDMA). The UMTS also supports enhanced 3G data communications protocols, such as High Speed Packet Access (HSPA), which provides higher data transfer speeds and capacity to associated UMTS networks.
One problem may occur, for example, in UMTS networks, when a user equipment (UE) in Forward Access Channel (Cell_FACH) or Paging Channel (Cell_PCH) states, for example, moves from one cell to another cell, which causes the UE to trigger a Cell Update procedure in the new cell. For example, as discussed in 3GPP Specification 25.331 (herein incorporated by reference), the cell update procedure (discussed, for example, in section 8.3.1) can be done periodically or can be triggered. The cell update can be triggered, for example, when a UE selects a new cell (e.g., cell reselection), responds to a paging message, fails to transmit a message or receive an acknowledged (e.g., radio link failure), and/or re-enters the service area. In some instances, the UE may have an active signaling connection where parts of a sequence (e.g., a service data unit) are sent between the UE and a network entity using multiple protocol data units (PDUs). When a cell update procedure between the UE and the network occurs before the messages at the UE or network side is sent, UE configuration information associated with the unsent messages does not match the updated UE configuration information associated with the cell update procedure. Subsequent use of stale information (e.g., based on non-current UE configuration information) included in the previously-received PDUs may cause connection problems between the UE and network (e.g., time outs, call drops, call delays, etc).
Therefore, improvements in handling of PDUs in during wireless communication are desired.